Method for seaming wide panels of EPDM membrane to form a composite EPDM roofing membrane

ABSTRACT

A method and apparatus for continuously seaming cured EPDM membrane to form a composite sheet of predetermined width and indefinite length. The method includes the steps of providing at least two rolls of cured EPDM membrane having longitudinal marginal edges and feeding the cured EPDM membrane from the at least two rolls in a first direction. The longitudinal marginal edges of the cured EPDM membranes are positioned in an overlapping relationship as the cured EPDM membranes are fed in the first direction and then the overlapping longitudinal marginal edges are continuously seamed to form a composite sheet of indefinite length.

This application is a divisional of application Ser. No. 09/197,140, nowU.S. Pat. No. 6,615,892, filed on Nov. 20, 1998, incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates generally to a wide panel seaming methodand apparatus for forming EPDM roofing membrane. More particularly, thepresent invention relates to a method and apparatus for continuouslyseaming cured stock wide panels of EPDM membrane to form a compositeEPDM roofing membrane of predetermined width and indefinite length.

BACKGROUND OF THE INVENTION

EPDM is used as a single ply roofing membrane material for coveringindustrial and commercial flat roofs. EPDM roofing membrane having athickness between {fraction (1/16)} inch and {fraction (3/32)} inch hasbeen found to constitute an extremely useful waterproof roofingmaterial, particularly for industrial and commercial buildings havingrelatively flat roofs of very large size. Such membranes are generallyapplied to the roof surface in a vulcanized or cured state. Because ofoutstanding weathering resistance and flexibility, cured EPDM basedroofing membrane has rapidly gained acceptance. Notwithstanding the wideacceptance of EPDM based roofing membrane, a disadvantage of utilizingthese elastomers is the lack of adhesion of EPDM, especially cured EPDM,to itself. Application of cured EPDM roofing membrane is typicallyhighly labor intensive because, in applying sheets of EPDM roofingmembrane to a roof, it is usually necessary to splice cured sheets ofEPDM roofing membrane together.

Typically, the roofing material comes in rolls and is rolled on instrips running the length of the building with a slight overlap betweenadjacent strips to provide a lap joint. Unfortunately, in the past suchroofing material has typically been available only in rolls ofrelatively narrow width, for example, four feet wide. For a roof oflarge dimensions, such as 200 feet by 400 feet, the time required toapply the roofing material strips of narrow width becomes excessive and,in light of today's high labor casts, relatively expensive. To reducethe application time, and hence the cost, of roofing with EPDM sheetstock, it is desirable to provide the sheet stock in rolls of very largewidth, such as forty feet or more wide. With sheet stock of such width,a roof measuring 200 feet by 400 feet can be applied in five 40-foot by200-foot strips. The time required to roof a building in this manner isa mere fraction, of that previously necessary with sheet stock ofnarrower width, e.g., 4 feet wide. This invention relates to a methodand apparatus for providing indefinite length stock of very large widthsynthetic rubber sheeting, e.g., EPDM membrane, from indefinite lengthstock of relatively narrower width.

Accordingly, it is an object of this invention to provide indefinitelength sheet stock of synthetic rubber of extremely large width, e.g.,forty feet or more. This object has been accomplished in accordance withcertain of the principles of this invention by providing means to feedout in a horizontal direction from a feed roll or the like, a pluralityof rolls of stock synthetic rubber roofing, the length being equal tothe length of the desired final stock and the width being equal to thecombined width of the rolls.

SUMMARY OF THE INVENTION

Briefly, according to the present invention there is provided a methodof continuously seaming cured wide panels of EPDM membrane to form acomposite sheet of predetermined width and indefinite length. The methodincludes the steps of providing at least two rolls of wide panels ofcured EPDM membrane having longitudinal marginal edges and feeding thewide panels of cured EPDM roofing membranes from the at least two rollsof stock roofing membrane in a first direction. The longitudinalmarginal edges of the wide panels of cured EPDM membranes are positionedin an overlapping relationship as the wide panels of cured EPDMmembranes are fed in the first direction and then the overlappinglongitudinal marginal edges are continuously seamed to form a compositesheet of EPDM roofing membrane of indefinite length.

The apparatus for continuously seaming wide panels of cured EPDMmembrane to form a composite roofing membrane of predetermined width andindefinite length includes at least two supply stations, a seamingstation and a storage station. The at least two supply stations supplyand simultaneously position indefinite length stock of wide panel curedEPDM membrane in an overlapping relationship. The seaming stationcontinuously seams the overlapping cured EPDM membranes to form acomposite roofing membrane of predetermined width and indefinite lengthand the storage station continuously reels the composite roofingmembrane for storage.

DESCRITPTION OF THE DRAWINGS

These and other features, advantages, and objectives of the inventionwill become more readily apparent from a detailed description thereoftaken in conjunction with the drawings in which:

FIG. 1 is a perspective view of three rolls of overlapping cured stockwide panels of EPDM roofing membrane containing an adhesive along thetop marginal edge;

FIG. 2 is a perspective view of three rolls of overlapping adhesive freecured stock wide panels of EPDM roofing membrane;

FIG. 3 is a perspective view of an apparatus for seaming wide panels ofEPDM membrane in accordance with one aspect of the present invention;

FIG. 4 is an enlarged partial perspective view of a seaming station ofthe apparatus of FIG. 3;

FIG. 5 is a cross-sectional view of the seaming station of the apparatusof FIG. 3 for applying adhesive between the wide panels of EPDMmembrane;

FIG. 6 is a cross-sectional view of the apparatus of FIG. 3; and

FIG. 7 is a cross-sectional view of an alternate embodiment of anapparatus for seaming wide panels of EPDM membrane in accordance withanother aspect of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings wherein like reference characters representlike elements there is shown an apparatus 10 for forming a compositeroofing membrane 12 of cured EPDM membrane 14. The apparatus 10 of thepresent invention is designed to form an indefinite length compositeroofing membrane 12 of predetermined width, for example, 100 feet, froman indefinite length panel of much smaller width, e.g., 10 feet. A 100foot wide roll of composite roofing membrane 12 is more convenient anduseful in covering very large surfaces such as the roof of a largebuilding. The time required to cover a large roof with conventionalroofing membrane of relatively narrower width is many times thatrequired to cover the same roof with composite roofing membrane formedin accordance with the present invention.

Referring to the figures, an apparatus 10 for forming an indefinitelength composite roofing membrane 12 is shown. The apparatus 10 includesat least two supply stations 16 which supply indefinite length stock ofwide panel cured EPDM membrane 14 or other similar olefin type polymers(FIGS. 3, 6 and 7). The term “EPDM” is intended to mean a terpolymer ofethylene, propylene and a diene monomer.

In one embodiment, at least one marginal edge 18 of the cured EPDMmembrane 14 includes a preapplied adhesive 20 (FIG. 1). The adhesive 20may be a thermoplastic elastomer (TPE), thermoplastic polyolefin (TPO)or suitable thermoplastic adhesive of a type well known in the art. Theterm “thermoplastic elastomer” refers to an elastomer that can bemelt-processed (as contrasted with conventional cross-linked rubbers).The term “thermoplastic polyolefin” refers to uncrosslinked polyolefinsthat are thermoplastic. The thermoplastic polyolefins are made byblending ethylene-propylene polymers with polypropylene. Theethylene-propylene polymers may be blended with polypropylene byconventional mixing techniques. In an alternate embodiment,ethylene-propylene and polypropylene are made in a reactorsimultaneously creating a homogenous mixture. The polymer is formulatedwith stabilizers, pigments and antioxidants to obtain the appropriateadhesive properties. Preferred TPO's include ethylene-propylene rubberblended with polypropylene. The TPE's and TPO's can be applied usingconventional plastic techniques, such as extrusion and the like. In yetanother embodiment, the cured EPDM membrane 14 is free of adhesive (FIG.2).

The supply station 16 includes a supply roll 22 containing cured EPDMmembrane 14 of indefinite length and selected width wound on ahorizontal mandrel. The mandrel is suitably journaled for rotation aboutits respective horizontal axis. The supply station 16 also includes atensioning device 24 to maintain a constant tension on the cured EPDMmembrane 14 as the membrane is fed from the supply roll 22 to a storageroll 26. In a preferred embodiment, the tensioning device 24 includes anarray of rollers suitably supported for rotation about their respectivelongitudinal axes. As shown in FIG. 3, the tensioning device 24 includesa support roll 28 that supports the cured EPDM membrane 14 as themembrane is fed from the supply roll 22 and a tensioning roll 30pivotally connected to maintain a downward pressure on the cured EPDMmembrane between the supply roll and the support roll.

The supply station 16 feeds out a selected length of cured EPDM membrane14 in the direction of the seaming station 32. As shown in FIGS. 1-3,the supply stations 16 are arranged in an overlapping manner tofacilitate the overlapping of cured EPDM membrane. The supply stations16 may be arranged in an alternating overlapping arrangement (FIG. 3) orin a step-wise arrangement (FIGS. 1 and 2).

The seaming station 32, FIGS. 3-7, includes a frame member 34 supportinga press assembly 36 and a device 38 for seaming the overlapping curedEPDM membranes 14. In a preferred embodiment, the press assembly 36includes pinch rollers 40 and 40 a suitably supported for rotation abouttheir respective longitudinal axes. As the overlapping edges of thecured EPDM membranes 14 pass between pinch rollers 40 and 40 a, theopposing pinch rollers compress the overlapping edges thereby securingthe membranes together to form a seam and enhancing the permanency ofthe seam. It will be appreciated that the overlapping edges of the curedEPDM membranes 14 may be compressed using most any suitable apparatus aswell known in the art.

In one embodiment as shown in FIG. 7, the device 38 for seaming theoverlapping cured EPDM membranes 14 includes a plurality of hot air guns42 of a type well known in the roofing membrane art. It will beappreciated that a hot air gun 42 is used to operatively seam a roofingmembrane specially manufactured to include a preapplied adhesive of thetype described above to an opposing roofing membrane. The hot air gun 42is operatively attached to the frame member 34 above the overlappingedges and directed at the overlapping edges to heat the area of overlapto weld the overlapping cured EPDM membranes together and form a seam.

In yet another embodiment as shown in FIGS. 3-6, wherein the cured EPDMroofing membrane does not contain a preapplied adhesive, the device 38for seaming the overlapping cured EPDM membranes 14 includes an adhesiveapplicator 44 which applies adhesive to the marginal edge region of theupper surface of a lower wide panel of cured EPDM membrane and/or to themarginal edge region of the bottom surface of the upper wide panel ofcured EPDM membrane as it is fed through the adhesive applicator. Anycommercially available hot melt adhesive applicator 44, such asavailable from Norton or Pyles, can be utilized. The adhesive applicator44 may terminate flow of the adhesive from the applicator when themembrane is stopped to avoid undesired accumulation of adhesive on thecured EPDM membrane. The adhesive applicator 44 also prevents adhesive20 from being dispensed from the applicator when no cured EPDM membrane14 is present, whether or not the apparatus 10 is actually in operation.

The formed composite roofing membrane 12 from the seaming station 32 isthen conveyed to a storage station 46 (FIGS. 6 and 7). The storagestation 46 includes a rotatable take-up roll 48 onto which the compositeroofing membrane 12 is rolled for storage purposes. Following reeling ofthe composite roofing membrane 12 on the take-up roll 48 at thestorage-station 46, the take-up roll 48 is transported for use on a roofdeck or for storage and later application to a roof deck as describedabove. The take-up roll 48 is motor-driven to convey the cured EPDMmembrane 14 from the supply roll 22 to the storage roll 28. The speedand operation of the take-up roll 48 is controlled from a control panel.

The composite roofing membrane 12 may be cut to a desired length by aroofing membrane cutter (not shown) of a type well known in the art. Thecutter may be used to cut transversely across the fed-out compositeroofing membrane 12 when a desired length has been fed past the seamingstation 32 for the purpose of providing a cut sheet of desired lengthand width.

It will be appreciated that an important aspect of this inventioninheres in the fact that any number of wide panel cured EPDM membranes14 may be continuously joined together to form one large composite EPDMroofing membrane 12. Furthermore, a plurality of wider panel cured EPDMmembranes may be joined simultaneously on the apparatus 10 to formseparate larger composite EPDM roofing membranes.

The documents and patents described herein are hereby incorporated byreference.

Having described presently preferred embodiments of the presentinvention, the invention may be otherwise embodies within the scope ofthe appended claims.

1. A method for continuously seaming wide panels of cured EPDM membraneto form a composite roofing membrane of predetermined width andindefinite length comprising: providing at least two supply stations,each supply station including a supply roll of cured EPDM membrane woundon a mandrel; positioning the at least two supply stations such that amandrel of a supply station is positioned in overlapping relation to anadjacent mandrel for supplying and simultaneously positioning indefinitelength cured EPDM membrane in an overlapping relationship; providing aseaming station including a frame member supporting a press assembly anda device for seaming the overlapping cured EPDM membranes, the pressassembly including opposing pinch rollers; and continuously compressingthe overlapping edges of the cured EPDM membranes as the EPDM membranespass between the pinch rollers thereby continuously securing theoverlapping cured EPDM membranes together to form a continuous seam anda composite roofing membrane of predetermined width and indefinitelength.
 2. The method of claim 1 wherein the overlapping marginal edgesof the wide panels of cured EPDM membrane include a preapplied adhesivethere between.
 3. The method of claim 1 further comprising the step ofapplying an adhesive between the overlapping marginal edges of the widepanels of cured EPDM membrane.
 4. The method of claim 2 wherein theadhesive is selected from thermoplastic polyolefin or thermoplasticelastomer.
 5. The method of claim 3 wherein the adhesive is selectedfrom thermoplastic polyolefin or thermoplastic elastomer.
 6. The methodof claim 2 wherein the overlapping cured EPDM membranes are seamed byheating the area of overlap to weld the overlapping cured EPDM membranesand then compressing the area of overlap to form a seam.
 7. The methodof claim 1 wherein the overlapping cured EPDM membranes are seamed byapplying an adhesive between the overlapping cured EPDM membranes andthen compressing the area of overlap to form a seam.
 8. The method ofclaim 1 further comprising the step of cutting the composite roofingmembrane to a desired length.